Here are some terrible ideas:
They could do what the NHL does in the playoffs and make the refs tilt the game as much as they can to keep things close. If Canada starts to pull away from Italy in a game, the refs can start making a ton of calls on Canada, while ignoring everything Italy does, no matter how obvious. Its harder to pad a lead when your team is constantly killing penalties.
Or they could start combining lower ranked nations into a few better teams like Team Europe at the last World Cup. Perhaps putting random age restrictions only on the top 6 teams will help too. Canada can only send players under 25, USA can only send players 0ver 25. Russia has to send players between 23 ad 33, and Sweden has to send their junior team.
Or they could ban NHLers from competing, like at the last Olympics. Honestly, the NHL would probably prefer not to have their players risking injuries at the World Championships. If things are still lopsided, move on to removing KHL players next.